Conventionally, in a disk-like signal recording medium, target data are recorded by each sector, and recording and reproduction of data to and from the signal recording medium is carried out by using a signal recording/reproducing device.
For example, control of a fault in the signal recording area such as sectors of the signal recording medium is carried out as follows. When a fault is found in a sector at the stage of formatting the signal recording medium, the address of the sector having the fault is registered, that is, recorded in a predetermined area of the signal recording medium, and it is eliminated from allocation of the logical address.
FIG. 1 shows the steps at the time of inspection and shipment after manufacture of a hard disk, and FIG. 2 shows the steps at the time of inspection and shipment after manufacture of a floppy disk. As shown in FIGS. 1 and 2, fault control as described above is carried out at the inspection step (step S102 or S107) after the step of manufacturing a magnetic disk such as a hard disk or a floppy disk (step S101 or S106).
In the case of the hard disk, for example, it is discriminated whether or not there is a fault in the recording area (step S103), as shown in FIG. 1. If there is no fault, the hard disk is shipped as it is (step S104). If there is a fault, the map of the logical address is updated, that is, the fault sector is eliminated from allocation of the logical address so as to prevent data from being recorded into the fault sector (step S105), and then the hard disk is shipped (step S104).
In the case of the floppy disk, it is discriminated whether or not there is a fault in the recording area (step S108). If there is no fault, the floppy disk is shipped (step S109). If there is a fault, the floppy disk is not shipped (step S110).
Meanwhile, in an optical disc such as a magneto-optical disc, fault control as shown in FIGS. 3 and 4 is carried out. First, in FIG. 3, inspection is carried out (step S122) after manufacture (step S121). It is then discriminated whether or not there is a fault in the recording area (step S123). If there is a fault, the map of the logical address is updated so as to prevent data from being recorded in the fault sector (step S124), and then the optical disc is shipped (step S125).
Then, as shown in FIG. 4, after the optical disc such as the magneto-optical disc is purchased by a user (step S126), data are recorded (step S127). At this point, the recorded data are reproduced (step S128), and it is detected whether or not the recorded data could be reproduced (step S129). If the data could not be reproduced, data are rerecorded in a recordable sector (step S130), and the map is updated so as to prevent the data from being recorded in the fault sector (step S131).
If the recording/reproducing device for recording/reproducing signals to/from the signal recording medium has failed to reproduce data recorded on the signal recording medium, it carries out reproducing operation again after changing the tracking and the parameter of an equalizer which affect the reproducing characteristics.
The signal recording/reproducing device or recording medium driving device adds redundant bits for error correction to the data and then records the data to the signal recording medium, in order to improve the reliability of the data to be recorded.
Meanwhile, even if data reproduction is successfully carried out by re-try operation for data reproduction in the case where reproduction of the data recorded on the signal recording medium has failed, there is no guarantee that next reproduction will be successfully carried out. Rather, if data reproduction is successfully carried out by re-try operation with the parameters changed as described above, it should be assumed that the corresponding sector becomes very difficult to read and that the reliability of reproduction of that sector is lowered. Lowering of the reliability of data reproduction often proceeds with the lapse of time.
Namely, in the conventional signal recording/reproducing device, it is possible to prevent the initial fault detected and registered into the map at the manufacturing step from being used by a fault management method of eliminating the fault from allocation of logical addresses.
In the conventional signal recording/reproducing device, the retry operation is carried out to execute read-out operations again in the case where a data read out has failed. However, it has not been practiced to rewrite the sector which becomes difficult to read out into another signal recording region by e.g., the alternate shift processing, as the need arises.
As described above, conventionally, the reliability of future data recording and reproduction cannot be secured with respect to a portion in which the reliability is lowered during the use or a portion in which lowering of the reliability proceeds with the lapse of time.